The invention concerns a device for the regulation of a constant outflow from a liquid container, in particular from a rain reservoir, with an outflow opening for the liquid, wherein to the outflow opening is assigned a movable throttle element, which in dependence on the liquid level regulates the outflow of the liquid from the container.
Devices of this sort for the regulation of a constant outflow from a liquid container are known from the state of the technology in manifold types and styles. For the most part they make use of a float that follows the liquid level and operates the throttle element by way of a rod or the like.
In order to achieve a constant outflow from a liquid container, the outflow opening must be varied in dependence on the liquid level in the liquid container. In this the hydraulic relation governs according to the following formula: EQU Q=.mu.+A+.sqroot.(2+g+H)
in which the symbols represent:
Q outflow PA1 .mu. flow coefficient PA1 A passage area of the outflow opening PA1 g acceleration of the Earth PA1 H dammed-in height in front of the regulating element PA1 p pressure.
It is apparent from the formula that the area A, in dependence on the dammed-in height H, must be varied in order to maintain a constant outflow.
From DE 34 18 348 A1 a device is known of the type mentioned at the beginning that exhibits a regulator chamber with an inlet opening, with a first throttle element assigned to this, and also with an outflow opening, with a second throttle element assigned to this; in which device the two throttle elements are linked to each other so as to be fixed as regards rotation and are driven by a common float arranged in the regulator chamber. This sort of design of the device permits blockages in the region of the inlet opening of the regulator chamber to clear automatically.
Known from DE 39 14 702 A1 is a float-actuated device for the regulation of a constant outflow from a liquid container, in which device there is likewise present a regulator chamber with inlet- and outflow openings, with throttle elements assigned to these. A float arranged in the regulator chamber controls the course of the two throttle elements via control curves. This device is also suited for clearing blockages in the region of the inlet opening to the regulator chamber automatically. In addition, the regulator chamber is formed there as a bell. The airtight closing leads, in the event of a damming-in of liquid in the regulator chamber, to a compressing of the air found there and thus to a reduction in the maximum achievable liquid level in the outflow amount regulator, which can thereby build relatively little.
The disadvantage of the float construction for the regulation of a constant outflow from a liquid container is to be seen in the tall construction and consequent high cost, and further in the circumstance that with float constructions no high damming levels can be controlled, because the regulation of the constant outflow is limited by the maximal float position.